EM monitoring in HCT/Ps

What type of process EM samples to collect in manufacturing of Human Cellular and Tissue based Products (HCT/Ps). Should there be any sampling done on HCT/Ps or beginning of the process that would justify that excursion found on the plate is not from the environment or operator’s improper aseptic behavior but it is actually from the HCT/Ps?

Can some one help me with EM in manufacturing facility of HCT/Ps?